*BSD News Article 91277


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From: Tony Griffiths <tonyg@OntheNet.com.au>
Newsgroups: comp.unix.sco.misc,comp.unix.bsd.freebsd.misc,comp.unix.bsd.bsdi.misc,comp.sys.sgi.misc
Subject: Re: no such thing as a "general user community"
Date: Tue, 18 Mar 1997 16:36:43 +1000
Organization: On the Net (ISP on the Gold Coast, Australia)
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Matt Dillon wrote:
> 
Interesting stats...  Our news server is also HORRIBLY i/o bound.  I
added
some more ram which helped but the disks are still the bottleneck!

I've toyed with the idea of mounting the news filesystems 'async' to see
what affect that would have although I'm a little afraid of what the
result would
be if the system crashed!  Can anyone who has done this recommend async
mounting
as a reasonable solution to increase i/o thru-put? 

>     So, here the machine's cpu is sitting 60% idle, with the 10BaseT
>     maxed out and two of the three disks almost maxed out (modern disks
>     tend to max out at around 100 transactions/sec with moderate seeking).
>     Less then 5% of the cpu is being used by the interrupts generated by
>     all of this junk, and less then 10% of the I/O bus's bandwidth is
>     being used.  The only reason the machine is 60% idle rather then 90%
>     idle is due to the fact that there are over 250 *active* processes
>     running on it (supporting 80 or so newsfeeds, in this case).

It's also interesting that your Ethernet has a high collision rate as
does
ours.  A switching hub is going in over the next day or so with each
server
having a dedicated (full-duplex) port which will hopefully improve
things!

Tony